[feat] tauri-driver: Append platform-specific file extension to `tauri:options.application`

[kawadakk]

Describe the problem

tauri-driver lets you specify an application binary path in a platform-neutral manner. It does so by automatically rewriting a neutral WebDriver capability (tauri:options.application) to engine-specific one (e.g., webkitgtk:browserOptions.binary). However, this does not completely abstract away platform differences because you still need to include a file extension (.exe) on Windows and not on other platforms.

Describe the solution you'd like

tauri-driver could automatically append a platform-specific executable file extension.

Alternatives considered

Manual edit is possible but has the following downsides:

• If you forget to do this, diagnosing the problem can be hard (some test tools don't print the error, so you need tcpdump to check the error message)
• You need to be careful not to accidentally commit the change to a version control system

Some test tools (e.g., Selenium, WebdriverIO) allow you to programmatically generate WebDriver capabilities. This is not possible on others (e.g., wasm-bindgen-test-runner).

Additional context

No response